This invention relates generally to computer systems, and more particularly the invention relates to data transfer between a host computer and a peripheral memory device.
FIG. 1 illustrates a conventional computer system in which a host computer 10 is connected to peripheral devices through bus 12. The peripheral devices can include an I/O controller 14, a printer 16, and a memory device 18 such as a CD ROM. In transferring data from a CD ROM, the host computer 10 employs a procedure defined by the memory supplier in accessing the memory and establishing the transfer and control routine. Heretofore, the peripheral responds to data requests by retrieving the data from the medium, performing associated error correction and other tasks, and then temporarily storing the data in a buffer 20 within the peripheral. The data is then transferred over the bus to the host computer 10 at a later time when the bus becomes available for data transfer.
Thus, in prior art systems, a single command is sent to the CD ROM device and all processing associated with that command is performed in the device itself. This is an inefficient use of resources given that the host system typically has far greater processing and memory bandwidth. This increases the complexity and expense of the memory device.